Taxanes are diterpene compounds which find utility in the pharmaceutical field. For example, taxol, a taxane having the structure: ##STR1## where Ph is phenyl, Ac is acetyl and Bz is benzoyl, has been found to be an effective anticancer agent. Naturally occurring taxanes such as taxol may be found in plant materials, and have been isolated therefrom. Such taxanes may, however, be present in plant materials in relatively small amounts so that, in the case of taxoi, for example, large numbers of the slow-growing yew trees forming a source for the compound may be required. The art has thus continued to search for synthetic, including semi-synthetic routes for the preparation of taxanes such as taxol and analogs thereof, as well as routes for the preparation of intermediates used in the preparation of these compounds.